Add a VideoCoding::RegisterReceiveCodec method with payload_type

Intended to ease removal of VideoCodec::plType, separating video
coding from transport.

Bug: None
Change-Id: I0764f2f714eab9ee4c3e55751819cd5915fb37b6
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/181075
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31892}

modules/video_coding/video_receiver_unittest.cc

@@ -58,7 +58,8 @@ class TestVideoReceiver : public ::testing::Test {
     receiver_.RegisterExternalDecoder(&decoder_, kUnusedPayloadType);
     webrtc::test::CodecSettings(kVideoCodecVP8, &settings_);
     settings_.plType = kUnusedPayloadType;
-    EXPECT_EQ(0, receiver_.RegisterReceiveCodec(&settings_, 1));
+    EXPECT_EQ(
+        0, receiver_.RegisterReceiveCodec(kUnusedPayloadType, &settings_, 1));
 
     // Set protection mode.
     const size_t kMaxNackListSize = 250;